Sound recording and reproducing apparatus



0 E United States atettt inventors Georg Probst Munich; Walter Herterich, Dachau, Germany Appl.No. 587,920 Filed Oct. 19, 1966 Patented Dec. 29,1970 Assignee Grundig Elektro-Mechanische Versuchsanstalt, lnh.: Max Grundig Fuerth, Bayem, Germany Priority Nov. 24, 1965 Germany N0.E30521 SOUND RECORDING AND REPRODUCING APPARATUS 12 Claims, 9 Drawing Figs.

U.S. Cl 274/4, 74/665, 179/100.2, 242/200, 242/201 Int. Cl Gllb 5/00, G1 lb 5/32, F11137/00 Field of Search 274/4, 1 1,

1.1, 11.12; l79/l00.2, 100.22; 242/54.1, 55.12, 55.12R, 67.4; 74/61, 665G1, 665C; 346/136; 235/132 [5 6] References Cited UNITED STATES PATENTS 2,504,587 4/1950 Rey 274/11 2,894,700 7/1959 Roberts et al 179/100.2 2,714,512 8/1955 Reed 274/4 7 2,867,389 1/1959 Viets 274/4 3,214,987 11/1965 Schenek et a1.. 74/331 2,574,218 11/1951 Lynch 242/55.12 2,703,714 3/1955 Demby etal.

FOREIGN PATENTS 236,571 11/1925 Great Britain 179/100.2 236,237 10/1925 Great Britain 274/4 Primary Examiner-Samuel S. Matthews Assistant Examiner-Steven L. Stephan Attorney-Michael S. Striker ABSTRACT: A miniature tape recorder wherein the tape is stored on two reels in a separable magazine and whereih each reel carries a clutch component. The housing of the tape recorder accommodates two intermeshing spur gears which carry second clutch components and are movable axially, independently of each other and by a single shifter, so that their clutch elements can engage the clutch elements of the corresponding reels. The gears are driven by a battery-operated electric motor.

SOUND RECORDING AND REPRODUCING APPARATUS The present invention relates to magnetic sound-recording and reproducing apparatus. More particularly, the invention relates to improvements in miniature tape recorders of the type utilizing tape magazines. Still more particularly, the invention relates to improvements in tape recorders which can be furnished in sizes enabling the user'to conceal the tape recorder in his or her pocket.

In presently known miniature tape recorders, the reels are driven by a prime mover assembly which includes one or more friction drives, such as rubber wheels or' rubber belts receiving motion from an electric motor. In relatively large tape recorders, the drive normally comprises one or more V-belts. It was found that energy losses in miniature tape recorders utilizing such friction drives are much too high to warrant an economical operation. 7 s v Accordingly, it is an important object of our invention to provide a novel and improved taperecorder, particularly a miniature pocket-sized tape recorder, wherein the losses in energy due to friction are eliminated so that the recorder can use a relatively weak motor which consumes little energy but insures smooth advance'of tape at a desired constant speed.

Another object of the invention is to provide a miniature tape recorder wherein the transmission of motion from the motor of the prime mover assembly to the reels of a magazine takes place through a set of positivelydriven elements so that the speed of tape travel between the reelswill depend exclusively on the speed of the motor and on the finish of motiontransmitting elements but not on friction or similar variable factors.

A further object of the invention is to provide a tape recorder of the above-outlined characteristics which can be placed in different conditions, including recording, reproduction or rapid rewinding, in a very simple way and by resorting to a single actuating member.

An additional object of the invention is to provide a novel arrangement for changing the direction of movement of tape in a miniature tape recorder.

A concomitant object of the invention is to provide a miniature tape recorder whose prime mover assembly can drive the tape at a constant speed when the tape advances slowly during recording so that the sound is recorded without distortion and can be reproduced with a requisite degree of cleamess.

Another object of the invention is to provide a very simple prime mover assembly for use in a miniature tape recorder and to construct the assembly in such a way that it can transmit motion at a desired speed without necessitating the utilization of brakes, clutches and similar complicated, costly and bulky devices. Briefly stated, one feature of our invention resides in the provision of an apparatus for reproducing or recording sound on a tape whose ends are connected to the cores of two reels, particularly a miniature pocket-sized tape recorder which utilizes prefabricated tape magazines. The apparatus comprises a support, a pair of permanently meshing driver gears mounted in the support for rotation in opposite directions about spaced parallel axes and movable axially between operative and inoperative positions, prime mover means for rotating the gears and preferably including a battery-operated miniature electric motor which rotates one of the driver gears through the intermediary of a system of gears or another suitable power train which does not utilize a friction drive, and shifter means operatively connected with the driver gears and actuatable by hand to move one of the driver gears to inoperative position simultaneously with movement of the other driver gear to operative position in which the other gear can be coupled with one of the reels to unwind tape from the other reel, and vice versa.

The novel features which are considered as characteristic of the invention are set forth in particular ,in the appended claims.

The improved apparatus ,itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be'best understood upon FIG. 3 is a front elevational view of the tape recorder and illustrates the prime mover assembly for the driver gears;

FIG. 4 is a transverse horizontal section as seen in the direction of arrows from the line IV-IV of FIG. 2;

FIG. 5 is a top plan view of the magazine, further showing the sound head in a position it assumes during recording, reproduction or rapid rewinding;

FIG. 6 is a top plan view showing certain parts of the struc ture illustrated in FIG. 2 in positions they assume during recording;

FIG. 7 is a similar top plan view and illustrates the parts shown in FIG. 6 in positions they assume during reproduction;

FIG. 8 illustrates the parts of FIGS. 6. or 7. in positions they assume when the tape recorder is idle; and

FIG. 9 illustrates the parts of FIGS. 6, 7 or 8 in positions they assume during rapid rewinding of tape. onto the supply reel.

Referring to the drawingsin detail, and first to FIG. 1, there is shown a miniature pocket-sized tape-recorder which cornprises a main supportl which accommodates. the prime mover assembly and can also support a prefabricated magazine or cassette 2. The latter is shown in a raised position and is movable vertically downwardly in parallelism with the axes of its reels 50, 51. m

The support 1 comprises a base plate 3 and two cover plates or top plates 4, 5. The magazine 2 comprises a bottom panel 6 and a top panel 7. The plates 3, 4, 5 are connected by bolts and are held at a requisite distance from each other by tubular spacers or sleeves 8 so that the plate 4 is located substantially midway between the plates 3 and 5. The panels 6, 7 are also connected'to each other by bolts and are held apart by a set of tubular spacers or sleeves 9. It is clear that the support 1 and/or the housing of the magazine 2 can form a one-piece casing which may consist of metallic or plastic material. Furthermore, the support 1 and/or the magazine 2 may be accommodated in an outer shell, not shown.

The prime mover assembly comprisesa small electric motor 10 which is connected in circuit with a battery complement (not shown). Such battery complement maybe accommodated in the space between the plates 4, 5 above the motor 10.

Additional parts of the prime mover assembly, including a power train connecting the output shaft II of the motor 10 with one of the driver gears 15, 16 are shown in FIGS. 2 and 3. FIG. 2 illustrates the tape recorder on a scale 2:1, i.e., twice its actual size. The power 1, comprises a pinion 12 which is mounted on the output shaft 11 and meshes with an inter mediate gear 13 whose shaft is joumaled in the plates 3, 4 and carries a pinion 14 meshing with a large-diameter driver gear 15 axially movably mounted on a shaft 17 and disposed inthe space between the plates 3 and 4. The driver gear 15 is in permanent mesh with a small-diameter driver gear 16 which is axially movably mounted on a shaft 18. The driver gears 15, 16 respectively comprise downwardly extending hub portions 19, 20 provided with circumferential grooves 19a, 20a which receive arcuate motion transmitting portions 23a, 24a forming part of two wings 23, 24 on a tiltable rocker 21. The latter forms part of a shifter unit which further includes a manually actuatable selector 30. The rocker 221 preferably consists of thin elastically deformable sheet metal stock and isprovided gles to the axes of he shafts 17, 18. The planes of the wings 23, 24 make'an obt se angle so that the rocker 21 can be tilted perusal of the following detailed description of a specific em-' in the space betwe n'the bottom plate 3 and driver gears 15,

16. The hub portions 19, 20 are preferably integral with the "1 respective driver gears.

In FIG. 3, the rocker 21 is shown in an angular position in which the wing 23 maintains the larger driver gear 15 in an operative or raised position. At the same time, the wing 24 maintains the smaller driver gear 16 in an inoperative or lower position. The gears 15, 16 will respectively assume their inoperative and operative positions in response to tilting of the rocker 21 about the crest 22. During such tilting of the rocker 21, the gears 15, 16 respectively move axially along their shafts 17, 18 and the mutual inclination of the wings 23, 24 is such that the gear which is held in operative position is biased pled with one reel 50 of the magazine 2 when the latter is positioned in such a way that the axes of its reels 50, 51 coincide with the axes of the shafts 17, 18. If the motor is started, the

. driver gear unwinds tape 29 from the supply reel 51 and causes the core of the takeup reel 50 to collect such tape in a well-known manner.

The rocker 21 is attached to the support 1 by means of two bolts 25, 26 which are in mesh with the bottom plate 3 and simultaneously serve as a guide means for a reciprocable pusher 40 carrying a magnetic recording and reproducing sound head 41.

' The manually actuatable selector 30 of the shifter unit can turn the tape recorder off (FIG. 8) or to one of three on positions, namely, recording (FIGS. 2 and 6), reproducing (FIG. 7) and rapid rewinding (FIG. 9). The rapid rewinding position of the selector 30 is indicated in FIG. 2 by phantom lines. The selector 30 is reciprocable in the support 1 in directions indicated in FIG. 2 by a double-headed arrow 32 and ,is provided with elongated slots 33, 34 receiving the stems of two guide pins 35, 36 fixed to the base plate 3. A knob 31 of the selector 30 extends from the support 1 and can be shifted byhand to thereby change the angular position of the rocker 21. Suitable detent means may be provided to yieldably hold thelselector 30 in each of its four positions. Also, the support 1 may carry symbols to indicate the four positions of the selector. The latter comprises a projection or extension 37 which overlies the adjoining marginal portion of the rocker 21 and is movable from engagement with the wing 23 into engagement with the wing 24, or vice versa, as well as to a position directly above the crest 22. With reference to FIG. 2, the projection 37 can be moved along the lower marginal portions of the wings 23, 24.,and is shown in a position in which it engages with the wing 24 which causes the rocker 21 to hold the driver gear 15 in operative position. The same position of the projection 37 is shown in FIG. 6 whereas FIG. 7 shows the projection 37 still in engagement with the wing 24 but nearer to the crest 22. In FIG. 8, the projection 37 overlies the crest 22, and FIG. 9 shows the projection 37 in engagement with the wing 23. FIGS. 6 and 9 show the projection 37 in its two end positions. When moved to the position of FIG. 8, the projection 37 maintains the rocker 21 in an intermediate position in which the driver gears 15, 16 are held in a neutral position, namely, in a position in which neither of these gears is coupled to a reel in the magazine 2. The gears 15, 16 are then located in a common plane. By moving the projection 37 into engagement with the wing 23, the operator will cause the smaller gear 16 to assume its operative position and, by starting the motor 10, the gear 16 will rapidly rewind the tape 29 from the takeup reel 50 onto the supply reel 51.

Reciprocatory movements of the selector 30 are further utilized to move the aforementioned pusher 40 for the sound head, 41, The pusher 40 is biased by a helical contraction spring 42,;which operates between the head 41 and a fixed post carried by the support 1. This spring 42 maintains a follower 43 of the pusher 40 in engagement with a cam 38 extending along one edge of the selector 30. The aforementioned pins 25,- 26 enable the pusher 41) to move in directions at right angles to the direction of movement of the selector 30. The

pusher 40 is further guided by a third pin 27 and is provided with three elongated slots 45, 46, 47 which respectively receive the stems of the pins 25, 26 and 27. When the selector 30 is moved to the position shown in FIG. 8, the spring compels the follower 43 to enter a notch 39 of the cam 38 whereby the sound head 41 moves upwardly, as viewe dl'in FIGS. 2, 6 or 7. FIG. 3 shows that the sound head 41 is formed with a groove 41a which is located directly below its sensitive surface 41b and can receive a portion of the magazine 2 to hold the latter in requisite position'whenthe selector 30 maintains the tape recorder in one of its on" positions shown in FIGS. 6, 7 and 9. In the illustratedembodiment, the groove 41a of the sound head 41 can receive a marginal portion of the bottom panel 6. The magazine 2 can be moved to requisite position for engagement with the sound head 41 only when the selector 30 has been moved to the position of FIG. 8. In this way, the sound head 41 cannot engage the tape 29 during attachment of the magazine 2 so that the tape and/or the sound head is not damaged.

FIG. 2 further shows a normally closedrnaster switch 44 which opens automatically in response to entry of the follower 43 into the notch 39 of the cam 38. The master switch 44 is connected in circuit with the electric motor 10 and the latter is turned off in automatic response to movement of the selector 30 to the position shown in FIG. 8. The switch 44 then interrupts the flow of current to all other electrical components of the tape recorder. I

The structure shown in the drawings further comprises a carrier 60 for an erasing head 61. This carrier is shown in the form of a two-armed lever which is pivotably supported by a pin 64 and whose arm 63 carries the erasing head 61. The erasing head engages the tape 29 only in the recording position of the recorder, namely, in the position shown in FIG. 6. The other arm 65 of the carrier 60 has a cam face 66 which is in contact with a post 67 of the selector 30. The carrier 60 is biased by a helical contraction spring 62 which tends to maintain the cam face 66 in contact with the post 67. Thus, the carrier 60 rocks automatically in response to reciprocation of the selector 30, such rocking being indicated in FIG. 2 by a double-headed arrow 68. A stop pin 69 engages the arm 63 when the spring 62 is free to contract to thereby hold the erasing head 61 in an ineffective position. When the arm 63 engages with the stop pin 69 and the selector 3O continues to move in a direction to the left, as viewed in FIG. 2, the post 67 will move away from the cam face 66 on the arm 65, see FIGS. 8 and 9.

The driver gear 15 comprises an upwardly extending second hub portion 55 which carries a male portion of a coupling enabling the gear 15 to drive the reel 50. This male coupling portion comprises a pair of pins 55a which are receivable in bores 50a provided in a complementary female coupling portion of the core on the reel 50. The pins 55a will automatically enter the bores 50a in a single angular position of the hub 55; therefore, the wing 23 of the rocker 21 will undergo deformation while the hub 55 rotates with reference to the core of the reel 50 but the rocker will propel the gear 15 and its hub portion 55 upwardly as soon as the pins 55a move into accurate registry with the bores 50a. The reels 50, 51 are preferably of the flangeless type and are located in a common plane. The distance between the axes of the reels 50, 51 normally corresponds exactly to the distance between the axes of the shafts 17, 18. However, the cores of these reels are preferably mounted with a small radial clearance and the tips of the shafts 17, 18 are preferably rounded so that these shafts can readily find their way into the axial openings of the respective cores when the magazine 2 is placed onto the support 1. Such radial clearance between the cores of the reels 51), 51 and the panels 6, 7 of the magazine 2 is desirable to insure that the magazine can be properly positioned even if the user fails to move the magazine in exact parallelism with the axes of the shafts 17, 18.

The elasticity of the wings 23, 24 insures that the coupling pins 550,561: ofthe hub portions 55, 56 on the driver gears 15, 16 are biased upwardly and remain in the bores 50a, 510 as long as the respective gear 15 or 16 is held in operative position. The pins 56a of the hub 56 on the driver gear 16 will enter the bores 51a of the reel 51 when the projection 37 of the selector 30 is moved across the crest 22 of the rocker 21 and engages the wing 23. The gear 16 is then biased to its operative position and the pins 560 will penetrate into the bores 51a in response to less than one full revolution of the driver gear 16. The r.p.m. of the gear 15 is less than the r.p.m. of the gear 16 so that the latter can rapidly rewind the tape 29 onto the supply reel 51 when the selector 30 is moved to the position of FIG. 9.

The electric circuit of the tape recorder forms no part of the successful version of a pocket-sized tape recorder wherein a small battery or a complement of small batteries suffices to supply electrical energy to an electric motor. However, it isequally within the purview of the present invention to utilize a prime mover assembly which includes a spring motor and/or other types of positive power trains between the motor and the gears 15, 16.

An important feature of our invention resides in the surprising discovery that the tape 29 can be properly moved from the core of the supply reel 51 onto the coreof the takeup reel 50 despite the fact that the cores are driven by gears, i.e., not by belts, friction wheels and like prime mover assemblies which transmit motion by friction. It was found that the movement of tape is very satisfactory even at relativelyslow speeds which are required during recording or reproduction of sound, i.e., when the reel 50 is driven by the slowly rotating drivergear 15. The drive for the reels 50, 51 operates with a minimum of friction so that the wear on the power train 12-14 and driver gears l5, 16 is but a fraction of the wear on the components of drives in conventional miniature tape recorders which use friction wheels or the like. Also, the improved tape recorder can use a relatively weak motor. For example, and if the prime mover assembly utilizes an electric motor, such as the motor 10, the latter will consume about 20 milliwatts volts, 20 milliamperes) whereas the electric motor of the smallest presently known tape recorders consumes about 120 mil- .liwatts (4 volts, 30 milliamperes), i.e., six times the consumption of the motor 10. Due to greatly reduced frictional losses during the transmission of motion by meshing gears, the relatively small mass of the motor 10 can be used more effectively for smooth advance of the tape because the torque furnished by this motor at a given r.p.m. is much smaller than the torque which must be supplied by a motor driving a set of friction wheels or one or more endless belts and pulleys. The positive connections between the driver gears 15, 16 and the respective reels 50, 51 also contribute to smooth advance of the tape. The movement of tape in presently known miniature recorders utilizing friction drives is jerky because a nonpositive connection between a friction drive and the reels will invariably cause undesirable accelerationsand/or retardations of reels. In our tape recorder, the constancy of speed at which the tape 29 travels between the reels 50, 51 depends solely on a the motor speed and on the finish of gears 12 13, 14, 15 and 16.

Another important advantage of our recorder is that the prime mover assembly 10-14. need not utilize any brakes, clutches and like devices. This is due to the factthat the driver gears 15, 16 are in permanent mesh and rotate at a desired speed whenever the circuit of the motor 10 is completed by the master switch 44.

The tape 29 can be provided with two or more sound tracks. If the magazine 2 contains tape with two sound tracks, it will be detached from the shafts 17, 18 when the recordal of sound on one of the tracks is completed and .is placed back onto the support in inverted position in which the head 41 can record sound on the other track.

6 Without further analysis. the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it. for various applications 1. In an apparatus for reproducing and recording sound, in

combination; a support; a self-sustaining separable tape magazine including two reels arranged rotatably about sub stantially parallel axes and each of said reels comprising a first clutch component, said self-sustaining separable tape magazine mounted on said support; a pair of intermeshing spur gears mounted in said support for rotation in opposite directions about parallel axes, said gears including a larger gear and a smaller gear and each gear being shiftable axially with reference to the other gear between an operative and an inoperative position while remaining in mesh with the other gear; a pair of second clutch components, each being rotatable by one of said gears and shiftab le by the respective gear- -during shifting of the same between operative and inoperative positions-between a clutch-engaging position engaging the corresponding first clutch component on said reel and a clutch-disengaging position out of engagement with said first clutch component on said reel; prime mover means for rotating said gears whereby the speed of the smaller gear exceeds move said larger gear to its inoperative position in which the second clutch component shifted by said larger gear is in a clutch-disengaging position simultaneously with movement of the smaller gear to its operative position in which the second clutch component shifted by said smaller gear is in said clutch engaging position thereof in engagement with the first clutch component of the corresponding reel to drive such reel at a higher first speed and to thus unwind the'tape from the other reel at said higher first speed, or to move said smaller gear to its inoperative position in which the second clutch component shifted by said smaller gear is in its clutchsdisengaging position, simultaneously with movement of the larger gear to its operative position in which the second clutch component shifted by said larger gear is in said clutch-engaging position thereof in engagement with the first clutch component of the corresponding reel to drive such reel at a lower second speed and to thereby unwind the tape from theother reel at said lower second speed.

2. A structure as defined in claim 1, wherein said shifter means comprises a single manually operated member and further comprising a sound head, and means for moving said sound head into engagement with and away from the tape in the magazine in response to actuation of said single manually operated member.

3. A structure as defined in claim 1, wherein said prime mover means is operatively connected to one' of said gears so that the other gear is'rotated by said one gear.

4. A structure as defined in claim 1, wherein each of said second clutch components is rigid with the respective gear.

5. A structure as defined in claim 1, wherein said shifter means is further actuatable to move both said gears to their inerasing head, said lever being rockably secured to said support and having cam means provided on the other arm thereof, said shifter means comprising a selector reciprocably mounted on 1 said support and having a motion-transmitting:portion engageable with said cam, and furthercomprising means'for biasing said other-arm toward engagement of 'said carn with said mo tion-transmitting portion.

I selector assumes said recording position.

9. In an apparatus for reproducing and recording sound on tape whose ends are connected with two reels, particularly in a miniature'tape recorder for use with tape magazines, a sup port; a pair of interrneshing driver gears mounted in said support for rotation in opposite directions about parallel axes and each movable axially between an operative and an inoperative position; prime mover means for rotating said gears; and shifter means operatively connected with said gears and ac- I tuatable by hand to move one of said gears to its inoperative position simultaneously with movement of the other gear to its operative position in which said other gear is coupled with one .of the reels to unwind tape from the other reel, said shifter means comprising a rocker tiltable about a third axis extending at right angles to the axes of said gears and selector means for tilting said rocker, said selector means being reciprocable in said support in directions at right angles to the axes of said gears and at right angles to said third axis, said rocker comprising two mutually inclined wings meeting along said third axis and said selector means comprising a projection which engages one of said wings at a time whereby said rocker is tilted in response to movement of said projection from one to the other side of said third axis.

10. In an apparatus for reproducing and recording sound on a tape whose ends are connected with two reels, particularly in a miniature tape recorder for iise with tape magazines, a support; a pair of intermeshing driver gears mounted in said support for rotation in opposite directions about parallel axes and each movable axially between an operative and an inoperative position; prime mover means for. rotating said gears; shifter means operatively connectedwith said gears and actuatable by hand to move one of said gears to itsinoperative position simultaneously with movement of the, other gear to its operative position in which said other gear is coupled with one of the reels to unwind tape from the otherir eel, said shifter means being movable by hand between first arid second positions which respectively correspond to the operative position of said one and said other gear and a third position corresponding to inoperative positions of both said gears; a sound head; and means for moving said sound head into engagement with a" away from the tape in response to actuation of said shifter means, said sound head being provided with means for engaging a portion of a magazine whose reels are aligned with said driver gears to thereby hold such magazine against movement with reference to said support in the first and second positions of said shifter means.

11. A structure as set forth in claim 10, wherein said engaging means comprises a grooved portion of said sound head arranged to receive a portion of a magazine in the first and second positions of said shifter means.

12. A structure as set forth in claim 10, further comprising normally closed switch means and means for opening said switch means in response to disengagement of said sound head from a magazine. 

